SDS200: SDS200 Filters

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WX9RLT

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Can anyone tell us about the SDS200 filters?

What filters there are?
What do they do?
How do you use them personally on your scanner?



Thank you
 

iMONITOR

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Can anyone tell us about the SDS200 filters?

What filters there are?
What do they do?
How do you use them personally on your scanner?



Thank you
They're called "Global Audio Filters" not R.F. filters like you might expect:

Normal
Invert
Auto
Wide Normal
Wide Invert
Wide Auto
Off


I've never seen any clear definition as to what they do, when or why to use them. I know Uniden has been asked numerous times and I don't recall them ever responding with any kind of explanation. So it's more of a trial and error process. Wide Invert works best for MPSCS P25 simulcast here in Michigan.
 

fxdscon

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Can anyone tell us about the SDS200 filters?

What filters there are?
What do they do?
How do you use them personally on your scanner?

Thank you
There is a great deal of discussion in the forums at this link, but what it boils down to is which filter works best for you, at your specific location, depending on what you are monitoring, and what kind of local RF noise and/or interference at your location. In other words, experimentation along with trial and error is the approach. Someone else's settings may not work at all for your needs, and could even make your reception worse.


.
 

Ubbe

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It's one 10MHz wide physical filter but you change the IF frequency to it to detune the signal to cut off the signals at either higher frequencies or lower.


/Ubbe
 

iMONITOR

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Sorry fixed my original post #2 where I called them "Audio" filters. Should be "Auto". I could have sworn that's what I read on the menu screen. It didn't make sense when I read it. I've been staying at home way too long!


They're called Global Auto Filters:

Normal
Invert
Auto
Wide Normal
Wide Invert
Wide Auto
Off


I've never seen any clear definition as to what they do, when or why to use them. I know Uniden has been asked numerous times and I don't recall them ever responding with any kind of explanation. So it's more of a trial and error process. Wide Invert works best for MPSCS P25 simulcast here in Michigan.
 

werinshades

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These filters can also be set at the site/department level which is helpful if any other systems you're monitoring may get worse after you set them. Global is used for the entire scanner, but an individual site/department setting overrides the global setting.
 

N4DJC

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Anyone have ideas for air bands, railroads? I’m using invert currently.
 
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N4DJC

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The "Best" Filter is the one that works best for YOU.

There are no general rules for the proper filter.

Try until you find the one that works best. Nobody else knows!

See here:

Filters

A starting point for analog VHF might be helpful. I'm sure other's experiences would be helpful.
 

policefreak

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Berlin, NJ
One thing I have consistently observed on the SDS series is if I have the filter set on Wide Invert on a frequency in the 851 range the signal appears to be slightly attenuated. I get less signal bars, the RFFS goes down (more negative) and distant signals tend to break up. If I set the same frequency to the INVERT filter the signal appears slightly amplified. I get more bars, RFFS goes up (less negative) and the signal appears more susceptible to outside interference.
 

Ubbe

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The receiver in the SDS scanners, but not other Uniden models, uses an automatic gain control that will reduce the gain if it detects a strong signal in adjacent frequencies, and that are up +/-5Mhz from the one you are monitoring. I have the same in my AOR8200 and have the same problem but only with frequencies +/-0,5Mhz or less.

If you use the proper filter you may be able to block that other frequency from being detected and the receiver will go back to full gain and full sensitivity.

/Ubbe
 
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